Short version: R4DS freezes on "Loading..." screen. Is this likely a bad R4DS, or a bad microSD card?

Longer version: So, I ordered an R4DS with a 1GB C01G Japanese Kingston from dealextreme.com about two weeks ago and just received it two days ago.

Formatted the SD card in FAT32, put the English v1.10 kernel in the root, and put a few roms in the root as well (all done using the included silver USB microSD reader, which I'm lead to believe is safe).

Started off playing Ouendan - worked fine until a few stages in it froze. Tried again - froze at the same spot. So, I downloaded a different dump of the ROM, and was able to get past that area and couple others but froze yet again at another area.

So, I moved on to testing another ROM - Puyo Pop Fever - which worked until a few minutes in where the screen garbled up and froze.

Power-cycled NDS, and it froze on the "Loading..." screen.

So, my next thought was to reformat the microSD card and try out the v1.8 firmware that came on disc with the R4 - did that, and tried it out - first time, froze on "Loading..." screen again. Tried it again, and it actually booted to the R4 menu, but froze on that.

So, obviously, something's bad here, but my question is, does it sound more like a bad microSD card, or a bad R4DS? Naturally, I don't want to send back the R4 only to find that wasn't the issue, or vice-versa, so any help is appreciated!

So at one point it was freezing while just trying to boot to the R4 menu?

If so it sounds like it might be a lemon R4 or micro sd. ( i think R4 lemons are not common.)
The games may also be specifically labeled as problematic.

Check the R4 compatibility list on sorpei wiki to find out if it is the game.
You can bench the micro SD card to to see if it stacks up to the average specs that are listed for that particular card (listed in the GBATEMP wiki... under memory speed). (HDtach is the memory speed tester) If you have a lemon sd card, then the speeds should be way off, i think.

Always use the most up-to-date drivers. Anyone else?? sounds like the person is using all the right hardware and all. I also have the silver USB thingy. works great for me.

I had a similar situation when using my r4ds the first time. It would freeze on the loading bar when I had it formatted at FAT32 but after reformatting at FAT it worked fine. I then reformatted back to FAT32 and r4ds hasn't given me problems since.

Turns out it was a bad microSD card. I first tried reformatting the Kingston in FAT16 (32k clusters) and had the same problem, so I ran out to Best Buy and grabbed a 1gig San Disk. Formatted that in FAT16 from the start, put the v1.10 firmware on there, and all is well.

I'm going to assume that the Kingston was a lemon from the start, but I'm also a tad skeptical of the R4 card reader.

I know it's the supposedly safe silver one, but I'm just gonna' go buy another card reader just in case that had anything to do with it. I still don't know how a card reader could screw a card up beyond reformatting repair, but better safe than sorry, eh?